Cheap 12 V/230 V Invertor

Even though today’s electrical appliances are increasingly often self-powered, especially the portable ones you carry around when camping or holidaying in summer, you do still sometimes need a source of 230 V AC – and while we’re about it, why not at a frequency close to that of the mains? As long as the power required from such a source remains relatively low – here we’ve chosen 30 VA – it’s very easy to build an invertor with simple, cheap components that many electronics hobbyists may even already have.

Resistors
R1 = 18kOhm
R2 = 3kOhm3
R3 = 1kOhm
R4,R5 = 1kOhm5
R6 = VDR S10K250 (or S07K250)
P1 = 100 kOhm potentiometer
Capacitors
C1 = 330nF
C2 = 1000 µF 25V
Semiconductor
T1,T2 = MJ3001
IC1 = 555
IC2 = 4013
Miscellaneous
LA1 = neon light 230 V
F1 = fuse, 5A
TR1 = mains transformer, 2x9V 40VA (see text)
4 solder pins
PCB, ref. 080227-1 from www.thepcbshop.com